ays he cannot swear to the uplifted knife,
because his oculist tells him he is astigmatic, and vertical lines do
not affect him as do horizontal lines. Suppose another says that dots
have often danced before his eyes in very fantastic combinations, many
of which were very like one gentleman cutting another gentleman's
throat at dinner. All these things refer to real experiences. There is
such a thing as myopia; there is such a thing as colour-blindness;
there is such a thing as astigmatism; there is such a thing as
shifting shapes swimming before the eyes. But what should we think of
a whole dinner party that could give nothing except these highly
scientific explanations when found in company with a corpse? I imagine
there are only two things we could think: either that they were all
drunk, or they were all murderers.

And yet there is an exception. If there were one man at table who was
admittedly _blind_, should we not give him the benefit of the doubt?
Should we not honestly feel that he was the exception that proved the
rule? The very fact that he could not have seen would remind us that
the other men must have seen. The very fact that he had no eyes must
remind us of eyes. A man can be blind; a man can be dead; a man can be
mad. But the comparison is necessarily weak, after all. For it is the
essence of madness to be unlike anything else in the world: which is
perhaps why so many men wiser than we have traced it to another.

Lastly, the literal maniac is different from all other persons in
dispute in this vital respect: that he is the only person whom we can,
with a final lucidity, declare that we do not want. He is almost
always miserable himself, and he always makes others miserable. But
this is not so with the mere invalid. The Eugenists would probably
answer all my examples by taking the case of marrying into a family
with consumption (or some such disease which they are fairly sure is
hereditary) and asking whether such cases at least are not clear cases
for a Eugenic intervention. Permit me to point out to them that they
once more make a confusion of thought. The sickness or soundness of a
consumptive may be a clear and calculable matter. The happiness or
unhappiness of a consumptive is quite another matter, and is not
calculable at all. What is the good of telling people that if they
marry for love, they may be punished by being the parents of Keats or
the parents of Stevenson? Keats died young; but he had